Treasury Secretary Steven Mnuchin, estimated to be worth $300 million, requested use of a government jet to whisk him and his third wife, Louise Linton, away to Europe this summer for their honeymoon, several people told ABC News on Wednesday.

A Treasury Department spokesman told ABC News that Mnuchin requested the jet because he's a member of the National Security Council and was very concerned about having access to secure communications. After Mnuchin's office put the request in writing, someone realized this was unnecessary, people with knowledge of the situation said, but it still triggered an "inquiry" by the Treasury Department's Office of Inspector General. An Air Force spokesman told ABC News it could cost about $25,000 an hour to operate a U.S. Air Force jet.

The traveling Mnuchins were scrutinized for their trip last month to Kentucky, which just so happened to coincide with the solar eclipse. Mnuchin's office said the couple was there solely for meetings on tax reform, and they will reimburse the government for Linton's travel, but that jaunt is also under review by the inspector general. This is the same outing where Linton posted a photo on Instagram of her glamorously stepping off of a government plane, hashtagging the various designers who outfitted her (#hermes #valentino). When a commenter called her out, Linton gave a response dripping in condescension: "Aw!! Did you think this was a personal trip?! Adorable! Did you think the US govt paid for our honeymoon or personal travel?!? Lololol." Well, now that you mention it … Catherine Garcia